You can lower the temperature about 1/2 degree when you go into lockdown. However, I never have, and have had some pretty good hatches (near 100%). My incubators don't have the greatest temperature control (they can keep it within a degree of what I want), so if I lowered my temperature just a little, it could harm the hatch by fluctuating too low. If you have an incubator with a great temperature control, go ahead and lower the temperature. If you can't, don't worry, your eggs will be fine.